1. Field of the Invention
The invention relates generally to apparatus for removal and replacement of mortice locks and similar locking structure with minimal damage to the lock. In particular, the invention relates to wrench structures which allow rapid removal of the cylinder of a mortice lock without damage to the keyway.
2. Description of the Prior Art
Mortice and mortice thumbturn locks, as well as similar locking apparatus, are widely used, particularly in metal doors such as are common in commercial buildings including motels, hotels, stores, and the like. The mortice lock includes a cylinder which is held in the door by a set screw or cylinder yoke. From time to time, such locks need to be replaced for differing reasons. Various tools have previously been employed by the locksmith to remove such locks. These prior tools, which include pliers, vice grips, pipe wrenches, etc., unfailingly causing damage to and mar the edges of the lock face. These previous practices typically have resulted in the need for replacing the complete cylinder and, in many instances, the keyway itself which is expensive and often difficult to obtain since many such keyways are master keyed or otherwise keyed to form a part of a series of locks. Accordingly, in situations where mortice locks are to be removed, replaced or installed, it is desirable not only to cause as little cosmetic damage to the lock as possible, but it is also necessary to prevent damage to the keyway due to the expense and difficulty of obtaining a new keyway or core which would have a pin setting compatible with locks already in place in a building or series of buildings. The present invention provides apparatus capable of removing and replacing standard mortice cylinder locks with minimal damage to the lock face and without damage to the core or keyway of the lock. Apparatus provided according to the invention includes wrench structures which fit about the face of the cylinder of the lock to allow the cylinder to be loosened even in situations where the cylinder threads are crossed or the cylinder is corroded. Use of the invention is facilitated by drilling of the lock to cut away the set screw or yoke, the wrenches of the invention being then particularly useful to remove the cylinder from an installed position. Further, the present wrench allows a new mortice lock to be rapidly installed with a minimum of effort and without damage, either cosmetic or otherwise, to the lock.